JP3248424B2 - Process for producing modified polyphenylene oxide, epoxy resin composition using modified polyphenylene oxide by this process, prepreg using this composition, and laminate using this prepreg - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a modified polyphenylene oxide, an epoxy resin composition using the modified polyphenylene oxide obtained by the method, a prepreg using the composition, and a laminate using the prepreg. It is useful for a laminate processed into a circuit board on which electronic components such as the above are mounted.

[0002]

2. Description of the Related Art Epoxy resin, epoxy resin curing agent,
And polyphenylene oxide (hereinafter referred to as PPO)
The laminated board in which the cured product of
It has been known for 70 years. A laminate made of a cured product of this type of polyphenylene oxide-epoxy resin-based thermosetting resin has excellent high-frequency characteristics, in particular, dielectric constant,
Since it has a dielectric loss tangent characteristic, it is suitable for the X band (10 GHz) region used in the satellite communication wave region.

[0003] However, high-molecular-weight PPO has a high melt viscosity associated with a high glass transition temperature, and therefore has poor molding processability for heating and pressing a prepreg containing this type of PPO.

[0004] In order to solve this problem, PPO has poor compatibility and has poor mechanical strength. However, in order to solve this problem, both are used as compatibilizers. Use of polymer grafts or block copolymers is contemplated. These copolymers are formed by reacting unmodified PPO-terminated phenolic hydroxyl groups with functional groups in other polymers. Examples of the PPO modified with these other polymers include a modified PPO having an epoxidized terminal by reacting PPO having an intrinsic viscosity of 0.6 or less with epichlorohydrin in the presence of a catalyst as disclosed in Japanese Patent Publication No. 53-12557. Japanese Patent Application Laid-Open No. 4-26142
No. 6, a method for producing a modified carboxylic acid terminal PPO by reacting a modified PPO having an epoxidized terminal with a polycarboxylic acid, and a method of reacting a modified PPO having an epoxidized terminal with a polyamine compound according to JP-A-4-80231. The terminal aminated modified PPO
A method for producing is known.

The modified PPO obtained by these methods has a high melt viscosity as described above, and as a result, the peeling strength of the copper foil of the laminated board is weak, so that a phenomenon occurs in which plating infiltrates between the layers of the prepreg, and the resin impregnation occurs. There is a problem of low solder heat resistance due to poor solderability.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to measure the peeling strength of metal foil, solder heat resistance, plating penetration, and high-frequency characteristics. A certain dielectric constant, a method for producing a modified polyphenylene oxide constituting an epoxy resin composition useful for producing a laminate having excellent dielectric loss tangent characteristics, an epoxy resin composition using the modified polyphenylene oxide, a prepreg using this composition, and An object of the present invention is to provide a laminate using the prepreg.

[0007]

According to a first aspect of the present invention, there is provided a method for producing a modified polyphenylene oxide, comprising the steps of:
A number average molecular weight of 10,000 to 30,000 high molecular weight polyphenylene oxide and a polyphenol compound and a number average molecular weight obtained by performing a redistribution reaction in the presence of a radical initiator, a phenol-modified polyphenylene oxide having a number average molecular weight of 1,000 to 3,000, and epichlorohydrin. The reaction causes a modified polyphenylene oxide having a low molecular weight with an epoxy group introduced into the terminal.

The epoxy resin composition according to a fourth aspect of the present invention comprises an epoxy resin, a modified polyphenylene oxide obtained by the production method according to the first to third aspects, and a curing agent for the epoxy resin as essential components. It is useful for the production of a laminate having excellent peeling strength of metal foil, solder heat resistance, plating penetration, and dielectric constant and dielectric loss tangent which are indicators of high frequency characteristics.

According to a fifth aspect of the present invention, there is provided a prepreg wherein a substrate is impregnated with the epoxy resin composition of the fourth aspect, and the epoxy resin and the epoxy-modified polyphenylene oxide in the epoxy resin composition are cured by a curing agent for the epoxy resin. It is semi-cured on the B stage, and has a metal foil peeling strength.
It is useful in the production of a laminate having excellent solder heat resistance, plating penetration, and a dielectric constant and a dielectric loss tangent characteristic which are indicators of high frequency characteristics.

A laminate according to a sixth aspect of the present invention is obtained by heating and pressing the prepreg of the fifth aspect. When the curing of the semi-cured epoxy resin in the prepreg is completed, the crosslinked structure of the cured epoxy resin is completed. And polyphenylene oxide. As a result, the metal foil is excellent in peel strength, solder heat resistance, plating penetration property, and dielectric constant and dielectric loss tangent which are indicators of high frequency characteristics.

Hereinafter, embodiments of the present invention will be described in detail.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The modified polyphenylene oxide produced by the production method of the present invention is a modified PPO having an epoxy group introduced into a terminal. The modified PPO is involved in the crosslinked structure of the cured epoxy resin, and causes a redistribution reaction of a high-molecular PPO having a number average molecular weight of 10,000 to 30,000 in the presence of a phenolic compound and a radical initiator of the high-molecular PPO. Thus, a low-molecular-weight phenol-modified PPO having a phenolic hydroxyl group of a phenolic compound at a terminal is used as a raw material,
Is limited to a number average molecular weight of 1,000 to 3,000. That is, the number average molecular weight of the phenol-modified PPO is 100
If the value is less than 0, the heat resistance of the laminate decreases, and if it exceeds 3000, the melt viscosity of the semi-cured product of the epoxy resin impregnated in the base material transformed into the B stage increases, and as a result, the peel strength of the metal foil of the laminate is increased. This is because they impair the performance of solder heat resistance and plating penetration.

A typical example of the above-mentioned polymer PPO is poly (2,6-dimethyl-1,4-phenylene oxide). Such a polymer PPO can be produced, for example, by a synthesis method disclosed in the specification of US Pat. No. 4,059,568.

Examples of the phenolic compound used in the redistribution reaction of the high-molecular PPO include polyfunctional phenols having two or more phenolic hydroxyl groups in the molecule, such as polyphenols such as bisphenol A, phenol-novolak and cresol novolak. preferable. Examples of the radical initiator include dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butylperoxyhexyne 3, 2.5. -Dimethyl-2-2.5-
Di-tert-butylperoxyhexane, α · α′-
Bis (tert-butylperoxy-m-isopropyl) benzene [1.4 (or 1.3) -bis (ter
t-butylperoxyisopropyl) benzene] and benzoyl peroxide (hereinafter referred to as BPO). Although not a peroxide as an initiator, it is a commercially available initiator manufactured by Nippon Oil & Fats Co., Ltd. under the trade name “Biscumyl” (1 minute half-life temperature 3
30 ° C.) can also be used.

When a polymer PPO having a number average molecular weight of 10,000 to 30,000 and a phenolic compound are reacted in a solvent such as toluene or chloroform in the presence of a radical initiator, first, the polymer PPO is radicalized to form a linear chain. A redistribution reaction in which a cut low-molecular-weight PPO is generated proceeds, and the activated low-molecular-weight PPO reacts with a phenolic compound to convert a low-molecular-weight phenol having a phenolic hydroxyl group of a phenolic compound at a terminal. A PPO is generated.

The amount of benzoyl peroxide is as follows:
3 to 10 based on 100 parts by weight of polyphenylene ether
The appropriate amount of the phenolic compound is 3 to 20 parts by weight. That is, when the amounts of the benzoyl peroxide and the phenolic compound are excessively increased, the redistribution reaction proceeds excessively, and the number average molecular weight of the low molecular weight polyphenylene oxide decreases. As a result, the heat resistance decreases as described above. On the other hand, if the amount is too small, the redistribution reaction does not proceed and the number average molecular weight does not decrease.

The redistribution reaction is carried out at 80 to 120 ° C. in an aromatic hydrocarbon solvent such as toluene, benzene or xylene.
Heat for ~ 100 minutes. Through this redistribution reaction, a low-molecular-weight phenol-modified PPO having a phenolic hydroxyl group of a phenolic compound at its terminal is produced.

Next, a phenol-modified P composed of a low-molecular-weight PPO to form the modified polyphenylene oxide of the present invention.
The reaction between PO and epichlorohydrin will be described.

The number of moles of epichlorohydrin to be epoxidized by reacting with the phenolic hydroxyl group introduced into the terminal of the phenol-modified PPO is at least 1 times, preferably at least 2 times the ratio of the terminal phenolic hydroxyl group, The reaction conditions are preferably at 80 to 120 ° C for 1 to 10 hours. For this reaction, an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is effective, and at least 1 equivalent, preferably 1.2 equivalent, to the epoxy group of epichlorohydrin.
It is used in an amount of at least equivalent, particularly preferably at least 1.5 equivalent. In this reaction, the solvent used in the above-described redistribution of PPO may be continuously used, or may be switched to another solvent. After the reaction, the system is cooled and the product is poured into a poor solvent for PPO such as methanol to precipitate as a precipitate. The precipitate is separated by filtration, washed with water or methanol, and unreacted epichlorohydrin or After removing the catalyst, the catalyst is dried under reduced pressure at 50 to 80 ° C. to obtain the desired modified polyphenylene oxide of the present invention with high purity.

The modified polyphenylene oxide of the present invention thus obtained has a low melt viscosity and a high fluidity, and contains bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin. ,
Compatible with epoxy resins such as phenol novolak type epoxy resin, cresol novolak type epoxy resin, isocyanurate type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, biphenyl type epoxy resin and polyfunctional epoxy resin Provides an epoxy resin composition that constitutes a rich, homogeneous varnish.

The modified polyphenylene oxide of the present invention is also useful as a raw material for producing a terminal amine PPO or a terminal carboxylic acid PPO by reacting a polyamine or a polycarboxylic acid compound.

Next, the epoxy resin composition of the present invention used in the form of a varnish for impregnating a substrate will be described.
This epoxy resin composition contains an epoxy resin, the above-mentioned modified polyphenylene oxide, and a curing agent for the epoxy resin as essential components. The modified polyphenylene oxide is a resin having an epoxy group at a terminal. Thus, it acts as an epoxy resin component together with the above-mentioned epoxy resin compounded separately from this resin. Here, the epoxy resin, which is a main component of the epoxy resin composition, is not particularly limited as long as it is an epoxy resin used for a laminated board. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, isocyanurate type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, biphenyl type epoxy resin, and Examples thereof include polyfunctional epoxy resins, and these are used alone or in combination. Further, flame-retardant epoxy resins obtained by brominating these resins can also be used.

As a curing agent for these epoxy resins,
Examples thereof include commonly used amines such as primary and secondary amines, phenols containing polyphenols such as bisphenol A and bisphenol F, and acid anhydrides. These may be used alone or in combination.

For the curing reaction of the epoxy resin, if necessary, for example, an imidazole-based curing accelerator and other commonly used accelerators are added.

Here, referring to the curing mechanism of the epoxy resin composition, the modified PPO into which the epoxy group has been introduced is also bound to the main component epoxy resin by the curing agent.
Therefore, the modified PPO participates in the crosslinked structure of the epoxy resin.

The prepreg obtained by impregnating the above-mentioned epoxy resin composition in the form of a varnish into a glass cloth, a glass non-woven fabric or the like is used as an indicator of the peel strength of metal foil, solder heat resistance, plating penetration and high frequency characteristics. Dielectric constant,
A laminate having excellent dielectric loss tangent characteristics is provided.

This prepreg can be made by the following method. The substrate is impregnated with these resin varnishes by, for example, immersing the substrate in a varnish.
The resin content of the prepreg is not particularly limited.
Preferably it is 70% by weight. In addition, at the time of impregnation, if the resin varnish is kept at 25 to 35 ° C., the curing reaction of the curing agent with respect to the epoxy resin in the resin varnish can be prevented, and the impregnation property to the base material can be increased, and the characteristics of the laminate can be improved can do. In heating and drying after impregnating the resin varnish, a temperature of 80 to 180 ° C is preferable. The reason is,
If the heating and drying is insufficient, only the surface of the prepreg stops drying, and the solvent remains inside, causing distortion due to the difference in the concentration of the resin between the surface and the inside of the prepreg. Cracks occur. Also, if the prepreg surface is excessively heated and dried, the viscosity of the prepreg surface changes rapidly during the drying process, causing uneven streaks and resin sagging on the prepreg surface, resulting in uneven adhesion between the metal foil and the prepreg. Large and small unevenness in the peeling strength of the foil, the heat resistance of the solder, and the dielectric properties occur.

Examples of the substrate include glass cloth, aramid cloth, polyester cloth, pulp paper, linter paper and the like.

Next, the laminate of the present invention will be described. If several of the above prepregs are required, metal foils are laminated to form a pressed body, and the pressed body is heated and pressed to obtain a laminated plate. As the metal foil, a copper foil, an aluminum foil or the like is used.
Pressing is performed for joining the metal foil and sheet and adjusting the thickness, so that the pressing conditions can be selected as necessary. Further, since the crosslinking reaction between the modified polyphenylene oxide, the epoxy resin, and the curing agent of these epoxy resins mainly depends on the reaction characteristics of the curing agent, the heating temperature and heating time are selected according to the type of the curing agent. For example,
Generally, temperature 150-300 ° C, pressure 50kg / c
The standard is about m ² and the time is about 10 to 60 minutes.

The metal foil-clad laminate thus obtained does not impair the properties of the epoxy resin and the polyphenylene oxide, has excellent high-frequency properties such as dielectric properties, and has heat resistance and adhesive strength that affect solder heat resistance. The processability such as through holes and punching due to the strength and the reliability of the penetration of the plating solution are also excellent.

The epoxy resin composition of the present invention is not limited to an example of use as a prepreg by forming a resin varnish through a solvent, impregnating the resin varnish into a substrate such as a glass cloth and drying the resin varnish. A sheet containing no base material can be prepared by the method, and this sheet can be used as a prepreg. When using this casting method, for example, a varnish is applied to a release sheet such as a polyester film or a polyimide film insoluble in a solvent for the varnish to a thickness of 5 to 700 μm and dried sufficiently.
Compared with the extrusion molding in which the blended resin is melted by heat, it is excellent in that a sheet can be easily produced at a relatively low temperature. The varnish-casting sheet is practical because the use of a sheet surface-treated with a release agent facilitates peeling.

Hereinafter, embodiments of the present invention will be specifically described with reference to examples.

[0033]

【Example】

(Example 1) First, a polymer PPO having a number average molecular weight Mn = 20,000 (manufactured by GE Plastics Japan) 10
0 parts by weight (hereinafter referred to as "parts"), 6 parts of benzoyl peroxide, and bisphenol A6 of a phenolic compound
100 parts of toluene was added thereto, and the mixture was stirred at 90 ° C. for 60 minutes, and subjected to a redistribution reaction to obtain a low-molecular-weight phenol-modified PPO having a phenolic hydroxyl group of a phenolic compound at its terminal.
Was obtained. This solution was subjected to gel permeation chromatography (column composition: SuperHM-M (1) from Tosoh Corporation) + SuperH
As a result of measuring the molecular weight distribution by M-H (1 line), the number average molecular weight was 2,300.

Next, 8 parts of epichlorohydrin and 8 parts of an aqueous sodium hydroxide solution (50%) were added to 210 parts of this solution, stirred at 100 ° C. for 4 hours, cooled to room temperature, and 1 liter of methanol was added. Was introduced to precipitate the denatured PPO. The precipitate was separated by filtration, washed twice with 1 liter of methanol and 1 liter of water, finally, washed with 1 liter of methanol, and dried at 70 ° C. under reduced pressure.
The modified polyphenylene oxide (modified PPO (A)) was purified.

The conversion between the phenol-modified PPO and epichlorohydrin was 91%. This reaction rate is
The 1.5% by weight of the carbon tetrachloride solution was measured for its infrared spectrum using a quartz cell having an optical path length of 10 mm, and the absorbance of the phenolic hydroxyl group before and after the reaction (3622 cm ^-1 ) was determined.

(Examples 2 and 3) Using the phenol-modified PPO solution obtained in Example 1 and reacting epichlorohydrin under the same conditions as in Example 1 based on the composition shown in Table 1, the epoxy group was added. Modified polyphenylene oxide of the present invention (modified PPO (B)), (modified PP
O (C) was obtained.

Example 4 Polymer PP used in Example 1
To 100 parts of O, 4 parts of benzoyl peroxide, and 4 parts of bisphenol A of a phenolic compound, toluene 10
0 parts were added and redistributed under the same reaction conditions as in Example 1 to obtain a solution of a low-molecular-weight phenol-modified PPO having a phenolic hydroxyl group of a phenolic compound at the terminal.
The number average molecular weight was 2,800.

Next, 4 parts of epichlorohydrin and 24 parts of an aqueous sodium hydroxide solution (50%) were added to 210 parts of this solution and reacted under the same conditions as in Example 1 to precipitate denatured PPO having an epoxy group introduced into the terminal. I let it. This precipitate was separated by filtration, washed twice with 1 liter of methanol and 1 liter of water, and finally washed with 1 liter of methanol.
And dried under reduced pressure, using modified polyphenylene oxide (modified P
PO (D)) was purified.

Example 5 Polymer PP used in Example 1
To 100 parts of O, 10 parts of benzoyl peroxide, and 10 parts of bisphenol A of a phenolic compound, 100 parts of toluene was added, and redistribution reaction was carried out under the same reaction conditions as in Example 1 to terminate the phenolic hydroxyl group of the phenolic compound. A solution of a low molecular weight phenol-modified PPO having the following formula: The number average molecular weight was 1,300.

Next, 24 parts of epichlorohydrin and 24 parts of sodium hydroxide aqueous solution (50%) were added to 210 parts of this solution.
The modified PPO having an epoxy group introduced at the terminal was precipitated by adding the same and reacting under the same conditions as in Example 1. The precipitate was filtered off and washed with 1 liter of methanol and 1 liter of water.
Wash twice, and finally with 1 liter of methanol, 70
After drying under reduced pressure at ℃, modified polyphenylene oxide (modified PPO (E)) was purified.

(Table 1) shows the modified P of Examples 1 to 5.
The mixing ratios of PPO, epichlorohydrin, and sodium hydroxide that produced PO (A), (B), (C), (D), and (E) are shown.

(Examples 6 to 10) Using the modified PPOs (A), (B) and (C) obtained in Examples 1 to 5, according to the mixing ratios of the components shown in Table 2 Place in a separable flask, stir at room temperature for 30 minutes, air-cool,
° C varnish was obtained. This varnish also has a low initial viscosity,
There was no precipitation phenomenon and the storage stability was excellent. After 24 hours, a 0.1 mm E glass cloth was impregnated with a resin varnish,
Drying at 4 ° C. for 4 minutes gave a prepreg having a resin content of 53% by weight. As shown in (Table 3), this prepreg had a smooth surface and no unevenness in impregnation of the resin, and supported the good impregnation of the varnish.

The results of evaluating the appearance, handleability and impregnation of the prepreg are shown in Table 3.

Next, eight prepregs are superimposed,
A copper foil of 18 μm was arranged on both sides to form a pressure-receiving body.
Heating and pressing was performed at 0 ° C. and a pressure of 20 kg / cm ² for 100 minutes to obtain a copper-clad laminate having copper foil laminated on both sides. The copper foil peeling strength, PCT solder heat resistance, dielectric constant,
And the dielectric loss tangent were measured, and the measurement results are shown in (Table 3).
Note that the dielectric constant and the dielectric loss tangent were based on measurement conditions specified in MIL.

[0045]

[Comparative example]

(Comparative Example 1) To 100 parts of toluene was added to 101 parts of the polymer PPO of Example 1, 1 part of benzoyl peroxide, and 1 part of bisphenol A of a phenolic compound at 90 ° C.
For 60 minutes, and a redistribution reaction was performed to obtain a phenol-modified PPO solution. The number average molecular weight of this phenol-modified PPO was 17000.

Next, 2 parts of epichlorohydrin and 2 parts of an aqueous sodium hydroxide solution (50%) were added to this solution, and the modified polyphenylene oxide (modified PPO (F) was purified under the same reaction conditions and processing conditions as in Example 1. The conversion was 92%.

Comparative Example 2 Polymer PPO10 of Example 1
1 part, 30 parts of benzoyl peroxide, and 30 parts of bisphenol A of phenolic compound
Was added and redistributed under the same conditions as in Comparative Example 1 to obtain a phenol-modified PPO solution. The number average molecular weight of this phenol-modified PPO was 700.

Next, 2 parts of epichlorohydrin and 2 parts of an aqueous sodium hydroxide solution (50%) were added to this solution, and the modified polyphenylene oxide (modified PPO (G) was purified under the same reaction conditions and processing conditions as in Example 1. .

Comparative Example 3 Polymer PPO10 of Example 1
To 1 part, 2 parts of benzoyl peroxide and 2 parts of bisphenol A of a phenolic compound, 100 parts of toluene was added and redistributed under the same conditions as in Comparative Example 1 to obtain a phenol-modified PPO solution. This phenol-modified PP
The number average molecular weight of O was 3,400.

Next, 2 parts of epichlorohydrin and 2 parts of an aqueous sodium hydroxide solution (50%) were added to this solution, and the modified polyphenylene oxide (modified PPO (H) was purified under the same reaction conditions and processing conditions as in Example 1. .

(Comparative Examples 4 to 6) Using the modified PPOs (F), (G) and (H) of Comparative Examples 1 to 3,
Varnishes were obtained under the same conditions as in Examples 6 to 10 according to the mixing ratios of the components shown in (Table 2). This varnish was impregnated and dried in the same E glass cloth as in the example under the same conditions to obtain a prepreg. Using this prepreg, a copper-clad laminate was obtained under the same conditions as in the example.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

Comparing the resin varnish characteristics, prepreg characteristics, and laminate characteristics of the examples and the comparative examples, the copper foil peeling strength, solder heat resistance, plating penetration property, and dielectric constant and dielectric loss tangent, which are indicators of high-frequency characteristics, are shown. It is apparent that the modified polyphenylene oxide of the present invention participates in the crosslinked structure constituting the cured product of the epoxy resin, because the impregnating property of the resin varnish is enhanced.

[0056]

According to the present invention, it is possible to provide a laminate excellent in the peeling strength of the metal foil, the solder heat resistance, the plating penetration property and the dielectric constant and the dielectric loss tangent characteristic which are indicators of the high frequency characteristics.

Continuation of the front page (72) Inventor Eiichiro Saito 1048 Odakadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A-9-202851 (JP, A) JP-A 47-32097 (JP, A) Japanese Patent Publication No. 50-15519 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 65/00-65/48

Claims (6)

(57) [Claims] 1. A compound having a number average molecular weight of 10,000 to 30,000
Reacting a high molecular weight polyphenylene oxide with a polyphenolic compound and a phenol-modified polyphenylene oxide having a number average molecular weight of 1,000 to 3,000 obtained by redistribution reaction in the presence of a radical initiator, and epichlorohydrin. A method for producing a modified polyphenylene oxide having epoxidized terminals. 2. The process for producing a modified polyphenylene oxide according to claim 1, wherein said radical initiator is benzoyl peroxide. 3. The process for producing a modified polyphenylene oxide according to claim 1, wherein an alkali metal hydroxide is used as a catalyst when reacting epichlorohydrin with the phenol-modified polyphenylene oxide. 4. An epoxy resin, according to claim 1, wherein
An epoxy resin composition comprising a modified polyphenylene oxide obtained by any one of the production methods and a curing agent for an epoxy resin. 5. A prepreg obtained by impregnating a substrate with the epoxy resin according to claim 4. 6. A laminate obtained by heating and pressing the prepreg according to claim 5.